Nonaqueous electrolyte secondary battery

Abstract

A non-aqueous electrolyte secondary battery having high input/output characteristics and preferable cycle characteristics is provided. A non-aqueous electrolyte according to one example of an embodiment includes a positive electrode which includes a positive electrode active material containing as a primary component, a lithium transition metal oxide having a layered structure, the content of Co of which is with respect to the total mass of metal elements except Li is 1 to 20 percent by mole; a negative electrode which includes a negative electrode active material containing Si; and a non-aqueous electrolyte which includes a fluorinated chain carboxylic acid ester.

1 . A non-aqueous electrolyte secondary battery comprising:
 a positive electrode which includes a positive electrode active material containing as a primary component, a lithium transition metal oxide which has a layered structure, the content of cobalt (Co) of which is with respect to the total mass of metal elements except lithium (Li) is 1 to less than 20 percent by mole;   a negative electrode which includes a negative electrode active material containing silicon (Si); and   a non-aqueous electrolyte which includes a fluorinated chain carboxylic acid ester.   
     
     
         2 . The non-aqueous electrolyte secondary battery according to  claim 1 ,
 wherein in the lithium transition metal oxide, the content of nickel (Ni) with respect to the total mass of the metal elements except Li is 80 percent by mole or more.   
     
     
         3 . The non-aqueous electrolyte secondary battery according to  claim 1 ,
 wherein the negative electrode active material is formed of a mixture of a silicon oxide represented by SiO x  (0.8≦x≦1.5) and graphite,   the content of the silicon oxide is with respect to the total weight of the negative electrode active material 1 to 20 percent by weight, and the content of the graphite is 80 to 99 percent by weight.   
     
     
         4 . The non-aqueous electrolyte secondary battery according to  claim 1 ,
 wherein the fluorinated chain carboxylic acid ester is a fluorinated propionic acid methyl ester.   
     
     
         5 . The non-aqueous electrolyte secondary battery according to  claim 1 ,
 wherein the content of the fluorinated chain carboxylic acid ester is with respect to the total volume of a nonaqueous solvent forming the non-aqueous electrolyte, 40 to 90 percent by volume.